The all or nothing law of action potentials mainly talks about how the axons in the neurons only fire when there is enough action potential to fire. If there is not enough action potential, then the neuron will not be able to send signals because the action potential does not fire because of the deficit.
Ventricular systole is when the ventricles of the heart as the result of electrical activity which helps to pump blood. During ventricular systole oxygenated blood is pumped from the left ventricle through the aortic valve and aorta. Simultaneously deoxygenated blood is pumped from the right ventricle through the pulmonic valve and pulmonary artery to the lungs. Using this explanation blood enters the aorta and pulmonary artery during ventricular systole. <span />